Stain treating composition

ABSTRACT

A two-compartment dispenser comprising a first compartment containing an aqueous composition comprising a source of active oxygen and a second compartment containing an aqueous composition comprising an alkalising agent.

This invention relates to an improved process for the removal of stainsfrom surfaces, preferably from fabric, and to compositions used in suchprocesses.

The use of oxygen bleaches with or without enzymes in compositions forstain removal has been known for a long time and many such compositionsare available. However a common difficulty in formulating such acomposition is to ensure that the bleach remains stable during storagebut is sufficiently active on use. This is particularly difficult toachieve in liquid compositions.

One solution has been to formulate liquid peroxygen bleaches at pHsbetween about 3 and 7 to produce a stable composition, but suchcompositions do not provide sufficient bleaching power to be useful formany household situations. Attempts have therefore also been made toformulate liquid peroxygen bleach compositions at pHs above this rangeto improve their performance. However these generally require expensivestabilising compounds to prevent loss of activity after manufacture.

The present invention provides a peroxide or peracid bleach productwhich has acceptable stability of the peroxide or peracid duringstorage, but which is capable of providing effective stain removal powerwhen used by the consumer.

WO 9731095 describes an apparatus for claiming surfaces that containstwo liquids that are mixed upon delivery to the surface. The firstliquid contains a hydrohalite bleach. The second liquid has a chelatingagent or a builder. The pH on mixture of the two liquids is about 11.

We have found that providing two separate compositions that are mixedduring, before or after (preferably during or before) application haveexcellent stability and performance.

Enzymes are a common component of stain treating compositions. Enzymeslose their cleaning performance in presence of a strong oxidant, such ashydrogen peroxide at alkaline pH. Surprisingly, we have found that bythe inclusion of a surfactant or a water-soluble polymer in either orboth of the separate compositions, (preferably present in at least theenzyme composition or both compositions) excellent cleaning performanceis achieved. Whilst not wishing to be bound by theory, it is believedthat the activity of the enzyme is maintained for a longer period afterthe peroxide composition is mixed with the enzyme composition by theprotective effects of surfactant micelles formed in the mixture.

According to the invention there is provided a process for stain removalat a surface, comprising applying to that surface an aqueous compositioncomprising a source of active oxygen, preferably of hydrogen peroxide ora source thereof, which composition has a pH of 7 or more and comprisesa mixture of:

-   -   (a) an aqueous composition comprising a source of active oxygen        having a pH of greater than 0 but less than 7 [hereinafter        component (a)] and    -   (b) an aqueous composition [hereinafter component (b)]        comprising an alkalising agent.

Preferably component(a) and/or component (b) additionally comprise atleast one surfactant or water-soluble polymer and are mixed not morethan two hours before being applied to the surface requiring stainremoval.

Preferably component (b) also contains at least one enzyme.

Sources of Active Oxygen

An essential ingredient is a source of active oxygen. A preferred sourceaccording to the present invention is hydrogen peroxide or sourcesthereof. As used herein a hydrogen peroxide source refers to anywater-soluble sources of hydrogen peroxide. Suitable water-solublesources of hydrogen peroxide for use herein include percarbonates,organic or inorganic peroxides and perborates.

Ideally, the pH of component (a) is less than 5, ideally less than 4,preferably less than 3. Preferably the pH of component (a) is greaterthan 1, greater than 2 or greater than 2.5.

Hydrogen peroxide or sources thereof provide from 0.1% to 15%,preferably from 0.5% to 10%, most preferably from 1% to 5% by weight ofthe total composition of active oxygen in component (a).

As used herein active oxygen concentration refers to the percentageconcentration of elemental oxygen, with an oxidation number zero, thatbeing reduced to water would be stoichiometrically equivalent to a givenpercentage concentration of a given peroxide compound, when the peroxidefunctionality of the peroxide compound is completely reduced to oxides.The active oxygen sources according to the present invention increasethe ability of the compositions to remove oxidisable stains, to destroymalodourous molecules and to kill germs.

The concentration of available oxygen can be determined by methods knownin the art, such as the iodimetric method, the permanganometric methodand the cerimetric method. Said methods and the criteria for the choiceof the appropriate method are described for example in “HydrogenPeroxide”, W. C. Schumo, C. N. Satterfield and R. L. Wentworth, ReinholdPublishing Corporation, New York, 1955 and “Organic Peroxides”, DanielSwern, Editor Wiley Int. Science, 1970.

Suitable organic and inorganic peroxides for use in the compositionsaccording to the present invention include diacyl and dialkyl peroxidessuch as dibenzoyl peroxide, dilauroyl peroxide, dicumyl peroxide,persulphuric acid and mixtures thereof. The component (a) according tothe present invention comprise from 0% to 15%, preferably from 0.005% to10%, by weight of the total composition of said organic or inorganicperoxides.

Suitable preformed peroxyacids for use in the compositions according tothe present invention include diperoxydodecandioic acid DPDA, magnesiumperphthalatic acid, perlauric acid, perbenzoic acid, diperoxyazelaicacid and mixtures thereof. The compositions according to the presentinvention comprise from 0% to 15%, preferably from 0.005% to 10%, byweight of the total composition of said preformed peroxyacids.

Optionally, component (a) or component (b) or both components (a) and(b) may additionally comprise from 0% to 30%, preferably from 2% to 20%,by weight of peracid precursors, i.e. compounds that upon reaction withhydrogen peroxide product peroxyacids. Examples of peracid precursorssuitable for use in the present invention can be found among the classesof anhydrides, amides, imides and esters such as acetyl triethylcitrate(ATC) described for instance in EP 91 87 0207, tetra acetylethylene diamine(TAED), succinic or maleic anhydrides.

pH

The pH of component (a) is preferably less than 7, ideally less than6.5, 6,0, 5.5, 5.0, 4.5, 4.0, 3.5 or 3.0. Ideally the pH is at least1.0, 1.5, 2.0 or 2.5.

The pH of component (b) is preferably greater than 7, ideally greaterthan 7.5, 8.0, 8.5, 9.0, 9.5 or 10.0. Ideally the pH is less than 13.0,12.5, 12.0 or 11.5.

The pH of either (a) or (b) can be adjusted by the addition of asuitable acid or base.

Alkalising Agent

As an essential element the compositions according to the presentinvention comprise an alkalising agent. The alkalising agent must besufficient to raise the pH of the [a] and [b] mixture to pH of greaterthan 8, ideally greater than 9, 10, 11 or 12. Ideally the pH is raisedup to 14, 13 or 12. Suitable alkalising agents are caustic alkalis suchas sodium hydroxide, potassium hydroxide and/or lithium hydroxide and/orthe alkali metal oxides such as sodium and/or potassium oxide. Apreferred source of alkalinity is a caustic alkali, more preferablysodium hydroxide and/or potassium hydroxide.

Ideally, an alkaline buffering means is also present. An alkalinebuffering means at a level of from 0.1% to 10% by weight of component(b). Preferably, component (b) herein comprise from 0.2% to 8% by weightof the total composition of a pH buffering means or a mixture thereof,preferably from 0.3% to 5%, more preferably from 0.3% to 3% and mostpreferably from 0.3% to 2%.

By “alkaline buffering means”, it is meant herein any compound whichwhen mixed with component (a) makes the resulting solution able toresist an increase in hydrogen ion concentration.

Preferred alkaline buffering means for use herein comprise an acidhaving its pK (if only one) or at least one of its pKs in the range from7.5 to 12.5, preferably from 8 to 10, and its conjugated base.

pK is defined according to the following equation:pK=−log Kwhere K is the Dissocation Constant of the weak acid in water andcorresponds to the following equation:[A][H]/[HA]=Kwhere HA is the acid and A is the conjugated base.

Preferably the alkaline buffering means herein consists of the weak acidas defined herein and its conjugate base at a weight ratio of the weakacid to its conjugate base of preferably 0.1:1 to 10:1, more preferably0.2:1 to 5:1. Highly preferred ratio of the weak acid to its conjugatebase is 1 since this is the best combination to achieve optimumbuffering capacity.

Preferably a given pH buffering means herein will be used to buffercompositions having a pH between pH=pK−1 and pH=pK+1 of each of its pK.

Effervescence

In one preferred embodiment of the invention an effervescent effect isachieved upon mixing (a) and (b). The effervescent agent containingcomponent preferably comprises a base, preferably present at a level offrom about 1% to about 10%, more preferably from about 2% to about 5% byweight of the compositions of the present invention. Preferably theeffervescent agent is in component (b).

Suitable bases for use in the effervescent agent-containing componentare selected from carbonates, bicarbonates, sesquicarbonates andmixtures thereof. Preferably, the base is selected from the groupconsisting of sodium carbonate, potassium carbonate, lithium carbonate,magnesium carbonate, calcium carbonate, ammonium carbonate, mono-, di-,tri-or tetra-alkyl or aryl, substituted or unsubstituted, ammoniumcarbonate, sodium bicarbonate, potassium bicarbonate, lithiumbicarbonate, magnesium bicarbonate, calcium bicarbonate, ammoniumbicarbonate, mono-, di-, tri-or tetra-alkyl or aryl, substituted orunsubstituted, ammonium bicarbonate and mixtures thereof.

The most preferred bases are selected from the group consisting ofsodium bicarbonate, monoethanol-ammonium bicarbonate and mixturesthereof.

In another preferred embodiment, the effervescent agent preferablycomprises a peroxide reducing enzyme that is held within component (b)[and (a) containing hydrogen peroxide], such as peroxidase, laccase,dioxygenase and/or catalase enzyme, preferably catalase enzyme,preferably present at a level of from about 0.001% to about 10%, morepreferably, from about 0.01% to about 5%, even more preferably fromabout 0.1% to about 1%, most preferably from about 0.1% to about 0.3% byweight of the compositions of the present invention. Catalase enzyme iscommercially available from Biozyme Laboratories under the trade nameCat-1A, which is a bovine liver derived catalyse enzyme; from GenencorInternational under the trade name Oxy-Gone 400, which is a bacterialderived catalyse enzyme; and from Novo Nordisk under the trade nameTerminox Ultra 50L.

Quick Breaking Foam

The effervescence system linked with the presence of surfactant islikely to produce foam upon mixing component (a) with component (b).However, it is not always desirable that the foam is one that is stablesince this may mean that the foam is difficult to rinse away or obscuresfrom the user the cleaning effect of the compositions.

Therefore, as a further feature of the invention the surfactant isselected from those that are capable of producing breaking foams.Preferably the foam breaks within 5 minutes of generation afterapplication to the surface, ideally less than 5, 4, 3, 2, or 1 minute.Preferably the foam does not break for at least 10, 20 or 30 seconds or1, 2 or 3 minutes. By the use of the term “break or breaks” we mean thatat least 50% of the volume of foam generated by the mixing of component(a) and (b) has disappeared without any form of physical or chemicalintervention.

Preferred surfactants to produce capable of performing a break are:

Anionic Surfactant

Preferred anionic surfactants capable of producing a breaking foam areethoxylated alkyl sulfates of the formula:RO(C₂H₄O)_(n)SO₃ ⁻M⁺

-   -   wherein R is a C₈-C₂₀ alkyl group, preferably C₁₀-C₁₈ such as a        C₁₂-C₁₆, n is at least 4, for example from 4 to 20, preferably 4        to 9, especially 4 to 6, and M is a salt-forming cation such as        lithium, sodium, potassium, ammonium, alkylammonium or        alkanolammonium.        Nonionic Surfactants

Preferred nonionic surfactants capable of producing a breaking foam arefatty alcohol ethoxylates, especially those of formula:R(C₂H₄O)_(n)OH

-   -   wherein R is a straight or branched C₈-C₁₆ alkyl group,        preferably a C₉-C₁₅, for example C₁₀-C₁₄, alkyl group and n is        at least 4, for example from 4 to 16, preferably 4 to 12, more        preferably 4 to 10.

Preferably the HLB value is greater than 9, ideally greater than 10.

The ethoxylated fatty alcohol nonionic surfactant will frequently have ahydrophilic-lipophilic balance (HLB) which ranges from 3 to 17, morepreferably from 6 to 15, most preferably from 10 to 15.

Examples of fatty alcohol ethoxylates are those made from alcohols of 12to 15 carbon atoms and which contain about 7 moles of ethylene oxide.Such materials are commercially marketed under the trademarks Neodol25-7 and Neodol 23-6.5 by Shell Chemical Company.

An additional or alternative group of preferred nonionic surfactants arethe polyoxyalkylated non-ionics of formula:R¹O[CH₂CH(R³)O]_(x)[CH₂]_(k)CH(OH)[CH₂]_(j)OR²

-   -   wherein R¹ and R² represent linear or branched chain, saturated        or unsaturated, aliphatic or aromatic hydrocarbon groups with        1-30 carbon atoms (presently 1 to 10) or one of R¹ and R² may be        a hydrogen, R³ represents a hydrogen atom or a methyl group, x        is a value between 2 and 30 and, k and j are values between 1        and 12, preferably between 1 and 5. R¹ and R² are preferably        linear or branched chain, saturated or unsaturated, aliphatic or        aromatic hydrocarbon groups with 6-22 carbon atoms, where group        with 8 to 18 carbon atoms are particularly preferred.        Particularly preferred values for x are comprised between 2 and        20, preferably between 4 and 15.

When x=2 or 3, the group R³ could be chosen to build ethylene oxide(R³=H) or propylene oxide (R³=methyl) units which can be used in everysingle order for instance (PO)(EO)(EO), (EO)(PO)(EO), (EO)(EO)(PO),(EO)(EO)(EO), (PO)(EO)(PO), (PO)(PO)(EO) and (PO)(PO)(PO). The value 2or 3 for x is only an example and bigger values can be chosen whereby ahigher number of variations of (EO) or (PO) units would arise.

Alternatively when x=2 or 3, the group R³ could be chosen to buildethylene oxide (R³=H) or propylene oxide (R³=methyl) units which can beused in every single order for instance (EO)(EO)(EO), (PO)(PO)(PO),(PO)(EO)(PO), (EO)(PO)(EO), (PO)(PO) and (EO)(EO). The value 2 or 3 forx is only an example and bigger values can be chosen .whereby a highernumber of variations of (EO) or (PO) units would arise.

Particularly preferred polyoxyalkylated alcohols of the above formulaare those where k=1 and j=1 originating molecules of simplified formula:

R¹O[CH₂CH(R³)O]_(x)CH₂CH(OH)CH₂OR². A suitable example is Biodac 232,available from Condea or Berol 185 from Akzo Nobel.

Enzyme

Where present said enzymes are preferably selected from cellulases,hemicellulases, peroxidases, proteases, gluco-amylases, amylases,xylanases, lipases, phospholipases, esterases, cutinases, pectinases,keratanases, reductases, oxidases, phenoloxidases, lipoxygenases,ligninases, pullulanases, tannases, pentosanases, malanases,beta-glucanases, arabinosidases, hyaluronidase, chondroitinase, laccaseor mixtures thereof.

Preferred enzymes include protease, amylase, lipase, peroxidases,cutinase and/or cellulase.

The cellulases usable in the present invention include both bacterial orfungal cellulase. Preferably, they will have a pH optimum of between 5and 12 and an activity above 50 CEVU (Cellulose Viscosity Unit).Suitable cellulases are disclosed in U.S. Pat. No. 4,435,307,JP-A-61078384 and WO-A-96/02653 which disclose fungal cellulasesproduced respectively from Humicola insolens, Trichoderma, Thielavia andSporotrichum. EP-A-739 982 describes cellulases isolated from novelBacillus species. Suitable cellulases are also disclosed inGB-A-2.075.028; GB-A-2.095.275; DE-OS-2.247.832 and WO-A-95/26398.

If present, cellulases are normally incorporated in the detergentcomposition at levels from 0.0001% to 2% of active enzyme by weight ofthe detergent composition.

Peroxidase enzymes are used in combination with oxygen sources, e.g.percarbonate, perborate, persulfate, hydrogen peroxide, etc. They areused for “solution bleaching”, i.e. to prevent transfer of dyes orpigments removed from substrates during wash operations to othersubstrates in the wash solution. Peroxidase enzymes are known in theart, and include, for example, horseradish peroxidase, ligninase andhaloperoxidase such as chloro- and bromo-peroxidase.Peroxidase-containing detergent compositions are disclosed, for example,in WO-A-89/099813, WO-A-89/09813 and in EP-A-540784. Also suitable isthe laccase enzyme.

If present, peroxidases are normally incorporated in the detergentcomposition at levels from 0.0001% to 2% of active enzyme by weight ofthe detergent composition.

Other preferred enzymes that can be included in the detergentcompositions of the present invention include lipases. Suitable lipaseenzymes for detergent usage include those produced by microorganisms ofthe Pseudomonas group, such as Pseudomonas stutzeri ATCC 19.154, asdisclosed in GB-A-1,372,034. Suitable lipases include those which show apositive immunological cross-reaction with the antibody of the lipase,produced by the microorganism Pseudomonas fluorescent IAM 1057. Thislipase is available from Amano Pharmaceutical Co. Ltd., Nagoya, Japan,under the trade name Lipase P “Amano,” hereinafter referred to as“Amano-P”. Other suitable commercial lipases include Amano-CES, lipasesex Chromobacter viscosum, e.g. Chromobacter viscosum var. lipolyticumNRRLB 3673 from Toyo Jozo Co., Tagata, Japan; Chromobacter viscosumlipases from U.S. Biochemical Corp., U.S.A. and Disoynth Co., TheNetherlands, and lipases ex Pseudomonas gladioli. Especially suitablelipases are lipases such as M1 Lipase™ and Lipomax™ (Gist-Brocades) andLipolase™ and Lipolase Ultra™ (Novo) which have found to be veryeffective when used in combination with the compositions of the presentinvention. Also suitables are the lipolytic enzymes described inEP-A-258068, WO-A-92/05249, WO-A-95/22615, WO-A-94/03578, WO-A-95/35381and WO-A-96/00292.

Also suitable are cutinases [EC 3.1.1.50] which can be considered as aspecial kind of lipase, namely lipases which do not require interfacialactivation. Addition of cutinases to detergent compositions have beendescribed in e.g. WO-A-88/09367; WO-A-90/09446, WO-A-94/14963 andWO-A-94/14964.

The lipases and/or cutinases are normally incorporated in either or bothcomposition at a level from 0.0001% to 2% of active enzyme by weight ofthe composition.

Suitable proteases are the subtilisins which are obtained fromparticular strains of B. subtilis and B. licheniformis (subtilisin BPNand BPN′). One suitable protease is obtained from a strain of Bacillus,having maximum activity throughout the pH range of 8-12, developed andsold as ESPERASE™ by Novo Industries A/S of Denmark, hereinafter “Novo”.The preparation of this enzyme and analogous enzymes is described inGB-A-1,243,784 to Novo. Other suitable proteases include ALCALASE™,DURAZYM™ and SAVINASE™ from Novo and MAXATASE™, MAXACAL™, PROPERASE™ andMAXAPEM™ (protein engineered Maxacal) from Gist-Brocades. Proteolyticenzymes also encompass modified bacterial serine proteases, such asthose described in EP-A-292623 (particularly pages 17, 24 and 98), andwhich is called herein “Protease B”, and in EP-A-199,404, which refersto a modified bacterial serine protealytic enzyme which is called“Protease A” herein. Suitable is what is called herein “Protease C”,which is a variant of an alkaline serine protease from Bacillus in whichlysine replaced arginine at position 27, tyrosine replaced valine atposition 104, serine replaced asparagine at position 123, and alaninereplaced threonine at position 274. Protease C is described inWO-A-91/06637. Genetically modified variants, particularly of ProteaseC, are also included herein.

High pH protease are preferred, such as from Bacillus sp. NCIMB 40338described in WO-A-93/18140. Enzymatic detergents comprising protease,one or more other enzymes, and a reversible protease inhibitor aredescribed in WO-A-92/03529. When desired, a protease having decreasedadsorption and increased hydrolysis is available as described inWO-A-95/07791. A recombinant trypsin-like protease for detergentssuitable herein is described in WO-A-94/25583. Other suitable proteasesare described in EP-A-516,200.

The proteolytic enzymes are incorporated in either or both compositionsat a level of from 0.0001% to 2%, preferably from 0.001% to 0.2%, morepreferably from 0.005% to 0.1% pure enzyme by weight of the composition.

Amylases (alpha and/or beta) can be included for removal ofcarbohydrate-based stains. WO-A-94/02597 describes cleaning compositionswhich incorporate mutant amylases. See also WO-A-95/10603. Otheramylases known for use in cleaning compositions include both alpha- andbeta-amylases. alpha-Amylases are known in the art and include thosedisclosed in U.S. Pat. No. 5,003,257; EP-A-252,666; WO-A-/91/00353;FR-A-2,676,456; EP-A-285,123; EP-A-525,610; EP-A-368,341; andGB-A-1,296,839. Other suitable amylases are stability-enhanced amylasesdescribed in WO-A-94/18314 and WO-A-96/05295 and amylase variants havingadditional modification in the immediate parent available from NovoNordisk A/S, disclosed in WO-A-95/10603. Also suitable are amylasesdescribed in EP-A-277,216, WO-A-95/26397 and WO-A-96/23873.

Examples of commercial alpha-amylases products are Purafect Ox Am™ fromGenencor and Termamyl™, Ban™, Fungamyl™ and Duramyl™, Natalase™ allavailable from Novo Nordisk A/S Denmark. WO-A-95/26397 describes othersuitable amylases: alpha-amylases characterised by having a specificactivity at least 25% higher than the specific activity of Termamyl™ ata temperature range of 25 DEG C. to 55 DEG C. and at a pH value in therange of 8 to 10, measured by the Phadebas™ alpha-amylase activityassay. Suitable are variants of the above enzymes, described inWO-A-96/23873. Other amylolytic enzymes with improved properties withrespect to the activity level and the combination of thermostability anda higher activity level are described in WO-A-95/35382.

Preferred amylase enzymes include those described in WO-A-95/26397 andin co-pending application by Novo Nordisk PCT/DK96/00056.

The amylolytic enzymes are incorporated in either or both compositionsat a level of from 0.0001% to 2%, preferably from 0.00018% to 0.06%,more preferably from 0.00024% to 0.048% pure enzyme by weight of thecomposition

Surfactant

Preferably, the total levels of surfactant are at levels of 0.1 to 25%wt, ideally from 1 to 10% wt.

Ideally, sufficient surfactant is present in each composition (a) and(b) such that upon mixture of (a) and (b) the critical micelleconcentration (CMC) is reached, i.e. the level above which formation ofmicelles occurs [typically measured by a change in physical properties,i.e. turbidity or conductivity],

Preferably non-ionic surfactants are used. Examples of non-ionicsurfactants are fatty acid alkoxylates, such as fatty acid ethoxylates,especially those of formula:R(C₂H₄O)_(n)OHwherein R is a straight or branched C₈-C₁₆ alkyl group, preferably aC₉-C₁₅, for example C₁₀-C₁₄, alkyl group and n is at least 1, forexample from 1 to 16, preferably 2 to 12, more preferably 3 to 10.

The alkoxylated fatty alcohol non-ionic surfactant will frequently havea hydrophilic-lipophilic balance (HLB) which ranges from 3 to 17, morepreferably from 6 to 15, most preferably from 7 to 13.

Examples of fatty alcohol ethoxylates are those made from alcohols of 12to 15 carbon atoms and which contain about 7 moles of ethylene oxide.Such materials are commercially marketed under the trademarks Neodol25-7 and Neodol 23-6.5 by Shell Chemical Company. Other useful Neodolsinclude Neodol 1-5, an ethoxylated fatty alcohol averaging 11 carbonatoms in its alkyl chain with about 5 moles of ethylene oxide; Neodol23-9, an ethoxylated primary C₁₂-C₁₃ alcohol having about 9 moles ofethylene oxide; and Neodol 91-10, an ethoxylated C₉-C₁₁ primary alcoholhaving about 10 moles of ethylene oxide.

Alcohol ethoxylates of this type have also been marketed by ShellChemical Company under the Dobanol trademark. Dobanol 91-5 is anethoxylated C₉-C₁₁ fatty alcohol with an average of 5 moles ethyleneoxide and Dobanol 25-7 is an ethoxylated C₁₂-C₁₅ fatty alcohol with anaverage of 7 moles of ethylene oxide per mole of fatty alcohol.

Other examples of suitable ethoxylated alcohol non-ionic surfactantsinclude Tergitol 15-S-7 and Tergitol 15-S-9, both of which are linearsecondary alcohol ethoxylates available from Union Carbide Corporation.Tergitol 15-S-7 is a mixed ethoxylated product of a C₁₁-C₁₅ linearsecondary alkanol with 7 moles of ethylene oxide and Tergitol 15-S-9 isthe same but with 9 moles of ethylene oxide.

Other suitable alcohol ethoxylated non-ionic surfactants are Neodol45-11, which is a similar ethylene oxide condensation products of afatty alcohol having 14-15 carbon atoms and the number of ethylene oxidegroups per mole being about 11. Such products are also available fromShell Chemical Company.

Further non-ionic surfactants are, for example, C₁₀-C₁₈ alkylpolyglycosides, such s C₁₂-C₁₆ alkyl polyglycosides, especially thepolyglucosides. These are especially useful when high foamingcompositions are desired. Further surfactants are polyhydroxy fatty acidamides, such as C₁₀-C₁₈ N-(3-methoxypropyl) glycamides and ethyleneoxide-propylene oxide block polymers of the Pluronic type.

The surfactant can also be an anionic surfactant. Such anionic surfaceactive agents are frequently provided in a salt form, such as alkalimetal salts, ammonium salts, amine salts, aminoalcohol salts ormagnesium salts. Contemplated as useful are one or more sulfate orsulfonate compounds including: alkyl sulfates, alkyl ether sulfates,alkylamidoether sulfates, alkylaryl polyether sulfates, monoglyceridesulfates, alkylsulfonates, alkylamide sulfonates, alkylarylsulfonates,olefinsulfonates, paraffin sulfonates, alkyl sulfosuccinates, alkylether sulfosuccinates, alkylamide sulfosuccinates, alkylsulfosuccinamate, alkyl sulfoacetates, alkyl phosphates, alkyl etherphosphates, acyl sarconsinates, acyl isethionates, and N-acyl taurates.Generally, the alkyl or acyl radical in these various compounds comprisea carbon chain containing 12 to 20 carbon atoms.

Particularly preferred are alkyl sulfate anionic surfactants. Mostpreferred are the non-ethoxylated C₁₂-₁₅ primary and secondary alkylsulfates, especially sodium lauryl sulfate.

In a further feature of the invention a surfactant is chosen to bepresent in either (a), (b) or both (a) and (b) that is capable offorming a stable foam. Such systems are described in EP0745665.

Polymer

Suitable polymers are those that are water-soluble and includepolycarboxylate polymer (such as those that can be purchased by Rohm andHaas under the Acusol 445N name) and polycarboxylic acid copolymers(such as can be purchased under the Sokalan CP9 name by BASF)

Compositions suitable for carrying out the invention may be provided asseparate components suitable for mixing by the consumer. Where thecompositions are suitable for mixing they may be mixed either directlyat the surface or remote from the surface before application.

Component (a) preferably comprises hydrogen peroxide or peracetic acid.

In accordance with the invention the two components (a) and (b) may bemixed in any suitable proportions, depending upon their initialconcentrations, suitably such that the finally applied mixture comprises0.01-30%, by weight of hydrogen peroxide or an organic peracid.Preferably, the ratio of component (a) to component (b) is from 10:1 to1:10, most preferably from 2:1 to 1:2.

When component (a) and (b) are mixed it is preferred that the pH of themixture is greater than 7, ideally greater than 8, 9, 10, 11 or 12.

It is preferred that the two components (a) and (b) are mixed no morethan 10 minutes before application to the surface requiring stainremoval.

It is most preferred that the two components (a) and (b) are mixed atthe surface requiring stain removal, so that the improved stain removaleffect may occur immediately.

In this aspect component (a) may be applied to the surface followed bycomponent (b) or vice versa. Alternatively (and preferably) components(a) and (b) are applied to the surface substantially simultaneouslywithin 30 seconds.

According to a preferred embodiment of the presentation invention, theconcentration of hydrogen peroxide or organic peracid in the compositionimmediately after mixing is from 0.01 to 10% w/w. This would mean forexample in a 1:1 mix of component (a) and (b) that component (a) priorto the mixing would contain from 0.02 to 20% w/w of hydrogen peroxide oran organic peracid.

Where component (a) comprises hydrogen peroxide it is most preferredthat the concentration of hydrogen peroxide in the mixture immediatelyafter mixing should be from 1.5 to 5% w/w. For example, if a 1:1 mixtureof components (a) and (b) is to be mixed, then component (a) shouldcomprise from 3 to 10% w/w hydrogen peroxide.

The concentration of the enzyme in component (b) will be less than 1%wt.

The process of the present invention alleviates the need to use furtherstabilising components for the hydrogen peroxide/organic peracid orenzyme when preparing commercial products.

The components suitable for use in the process according to theinvention may further include any other conventional additives known tothe art. Examples of these include fragrances, dyes, sequesterants,chelating agents, germicides, preservatives, corrosion inhibitors orantioxidants.

The above auxiliary components may be included in the compositionssuitable for use in the process of the present invention atconcentrations of from 0.01% w/w to 10% w/w. These auxiliary ingredientsmay be included in either component (a), or component (b) or both ifappropriate.

Compositions suitable for use in the process according to the presentinvention may be stored in any appropriate containers known to the art.For example, the two components may be stored in two-compartment packssuitable for sequential or simultaneous dispensing.

Where both components (a) and (b) are liquids, most preferably they maybe stored in a two-compartment dispenser, one compartment containingeach component and the dispenser being adapted to dispense eachcomponent on to a surface, either sequentially or, preferably,simultaneously.

According to a further aspect of the invention, there is provided atwo-compartment dispenser comprising

-   -   a first compartment containing an aqueous composition comprising        hydrogen peroxide or an organic peracid and having a pH of        greater than 0 but less than 7:    -   a second compartment containing an aqueous composition        comprising an alkalising agent and;    -   dispensing means adapted to dispense the contents (or part        thereof) of the compartments on to a surface either sequentially        or simultaneously to form a mixture thereof.

Preferably wherein the first compartment and/or the second compartmentadditionally comprise at least one surfactant or water-soluble polymer.

Preferably, the first compartment contains an aqueous compositioncomprising 3 to 10% w/w hydrogen peroxide; and the second compartmentcontains an aqueous composition comprising less than 1% w/w of anenzyme.

The invention will now be illustrated by the following Examples.

EXAMPLE 1

Compartment 1 % wt Hydrogen Peroxide 7.3 Oxo Alcohol C12-C15 5EO 7.0HEDP 0.12 Water up to 100 pH (100%) 3.8

Compartment 2 % Sodium Bicarbonate 10.0 Water up to 100 PH  8.5

EXAMPLE 2

First chamber % wt Water 71.8 Hydrogen peroxide 50% 14 Citric Acid 50%10 Chelating Agent 1 Sodium hydroxide 50% 3.2 Total 100.0

Second chamber % wt Water 73.58 Dowicil 75 0.050 Sodium boratedecahydrate 0.514 Trisodium citrate 1.3 Copolymer dispersant(25%) 0.200Enzyme 0.44 Sodium bicarbonate 4 Propylene glycol 4 Berol 185 15 Acusol0.7 Perfume 0.21 Total 100

EXAMPLE 3

First chamber % wt Water 71.8 Hydrogen peroxide 50% 14 Citric Acid 50%10 Chelating agent 40% 1 Sodium hydroxide 50% 3 Total 100

Second chamber % wt Water 70.586 Dowicil 75 0.05 Sodium boratedecahydrate 0.514 Trisodium citrate 1.3 Copolymer dispersant (25%) 0.2Enzyme 0.44 Sodium bicarbonate 4 Propylene glycol 4 Nonionic surfactant18 Acusol polymer(45%) 0.7 Perfume 0.21 Total 100

EXAMPLE 4

First chamber % wt Water 61.1985 Hydrogen peroxide 50% 14 Propyleneglycol 2 Nonionic surfactant 9 Citric Acid 50% 10 Chelating agent 40% 1Colour pigment 0.0015 Sodium hydroxide 50% 2.8 Total 100

Second chamber % wt Water 81.586 Dowicil 75 0.05 Sodium boratedecahydrate 0.514 Trisodium citrate 1.3 Copolymer dispersant (25%) 0.2Enzyme 0.44 Sodium bicarbonate 4 Propylene glycol 2 Nonionic surfactant9 Acusol polymer (45%) 0.7 Perfume 0.21

EXAMPLE 5

First chamber % wt Water 71. 8 Hydrogen peroxide 50% tech 14 Citric Acid50% 10 Pentasodium DTPA 40% 1 Sodium hydroxide 50% 3.2 Total 100

Second chamber % wt Water 73.586 Dowicil 75 0.05 Sodium boratedecahydrate 0.514 Trisodium citrate 1.3 Dispersant Polymer (25%) 0.2Enzyme 0.44 Sodium bicarbonate 4 Propylene glycol 4 Berol 185 15 Acusol(45%) 0.7 Perfume 0.21 Total 100

Conditions of test 1 ml of product was placed on the soil, scrubbed fivetimes by hand and left to react for 5 minutes. The materials were thenwashed in a US top loading washing-machine (Whirlpool Imperial) on thecycle for medium load at 30C temp with water of 12 F hardness and a1.5/1 Ca/Mg ratio. The materials were evaluated by measuring thereflectance (Y value) using a Ultrascan XE Spectrophotometer.

1. A process for stain removal at a surface, comprising applying to thatsurface an aqueous composition, which composition has a pH of 7 or moreand comprises a mixture of: component (a): an aqueous compositioncomprising a source of active oxygen and having a pH of greater than 0but less than 7 and component (b): an aqueous composition comprising analkalising agent.
 2. A process according to claim 1 wherein components(a) or (b) additionally comprise at least one surfactant orwater-soluble polymer.
 3. A process according to claim 2 whereincomponent (b) additionally comprises at least one enzyme.
 4. A processaccording to claim 2 wherein the surfactant is a non-ionic surfactant.5. A process according to claim 4 wherein component (a) or component (b)additionally contains a polycarboxylate.
 6. A process according to claim1 wherein the pH of component (b) is greater than
 9. 7. A processaccording to claim 1 wherein component (b) contains a pH buffer.
 8. Aprocess according to claim 1 wherein component (b) additionallycomprises an effervescent agent.
 9. A process according to claim 8wherein the effervescent agent is a base or is a peroxide reducingenzyme.
 10. A process according to claim 9 wherein the base is acarbonate or a bicarbonate.
 11. A process according to claim 2 whereinthe surfactant produces a foam upon mixing components (a) and (b).
 12. Aprocess according to claim 11 wherein the foam breaks.
 13. A processaccording to claim 11 wherein the foam reduces in volume by at least 50%in less than 5 minutes of its generation without any form of physical orchemical intervention.
 14. A process according to claim 2 whereinsurfactant is a nonionic surfactant having an HLB of greater than 10.15. A two-compartment dispenser comprising a first compartmentcontaining an aqueous composition comprising a source of active oxygenand having a pH of greater than 0 but less than 7; a second compartmentcontaining an aqueous composition comprising an alkalising agent; anddispensing means adapted to dispense the contents (or part thereof) ofthe compartments on to a surface either sequentially or simultaneouslyto form a mixture thereof.